"Sell it from a truck" is the "put a bird on it" of San Francisco retail. From bacon to flowers to booze, there's nothing that doesn't sound just slightly more desirable when it's hawked out of a truck. As a city, we've been captivated by Off the Grid, itinerant gift shops like Half Hitch, and TopShelf's former mobile boutique. We are, to put it crudely, truck suckers. But when we heard about online lingerie company True&Co.'s new bra truck, which opened temporarily at Proxy on Thursday, we did a, shall we say, double take. Given how unpleasant and intrusive lingerie shopping generally is, how could the experience of pawing through unmentionables be improved by parking them on a truck? At least the measuring tape lady would have less time to sneak up on us...right?

The only responsible option was to find out for ourselves, and so that's what we did: We tried on bras on a truck. On a cold day, no less.

LATEST SFGATE VIDEOS

The idea of the Try-On Truck, says True&Co. founder Michelle Lam, is to take the online shop on the road and give customers a chance to be fitted in person. "It's a personal shopping experience with bras outside the mall," she says. After Proxy, the truck will head to the ModCloth shop in Union Square, then Marin and Silicon Valley, followed by a yearlong national tour.

Perhaps inevitably for a venture in mobile retail, the Try-On Truck rolls several entrepreneurial cliches into one. The truck isn't just a truck; it's like a tiny home! Attendants aren't salespeople, they're "fit therapists"! And there is, of course, an algorithm: a proprietary fit quiz that analyzes sizing data from more than 2 million women and spits out recommendations for each customer, like Netflix for your boobs.

Cute startup jargon aside, the Try-On Truck actually makes lingerie shopping a tolerable, even pleasant, experience. The 300-square-foot shop, designed by Spiegel Aihara Workshop and Mobile Office Architects, isn't fully enclosed. But there are heaters in the dressing rooms (phew), with natural light pouring in through shades, for modesty. And there is, hallelujah, no measuring-tape lady. Instead, shoppers take the aforementioned fit quiz, which pinpoints size by taking into account how your current brand fits, along with past data from other shoppers. It also asks a lot of personal questions. We took the quiz at home the night before, and the "Are you a rightie or a leftie?" question was not answerable from memory. (Handy tip: have someone in the room you can flash for expediency's sake.)

More from San Francisco Magazine

Before 2 million women sized up their own breasts to build Lam's data set, she drafted the original algorithm using the results of a fitting marathon she conducted at home in 2012. She started with 500 bras bought on a credit card, tested out by parades of 10 women at a time to give feedback and compare sizing notes. "I was without any bra fitter training, testing the quiz with them and recommending bras," says Lam, whose shop sells her own line as well as a mix of other brands. "What I'd do was watch their eyes to see which ones made their eyes light up. That's the emotional winner."

When we arrived for our appointment, a fit therapist named Katherine ushered us into the largest, warmest fitting room. She showed us our fit recommendations on an iPad, asked a few polite questions about how our current bra is fitting, then disappeared. She returned with True&Co.'s bestseller, an in-house design called the Gramercy Balconette in black lace. Being a no-nonsense sort, we assumed the lacy stylings would put us off, or at least betray their texture beneath a T-shirt. But, aware that this dealie would set the tone for the rest of our fitting, we went for it. And, whoa, what a surprise. This was a laid-back, forget-you're-wearing-it kind of bra, comfy enough to be sold in a box with the phrase "18-hour" on the cover. Plus: cute!

When Katherine came back to gauge our reaction, we were sold. Finally, we said, a lace bra that isn't choking on frills. Breasts look feminine all by themselves—why must the Victoria's Secrets of the world tart them up as though we need help noticing that there are boobs in the vicinity? "Sometimes with lace you get a little too femine," Katherine agreed, with a chatty twinge of vocal fry. "What's great about this one is it has the scalloped edge and it does give you that round shape, but it comes in a lot of different sassy colors."

Beforehand, we had been a little worried about standing around in a bra with a stranger, but it all felt totally normal. Appointments at the Try-On Truck are more like a bridal-boutique session than the back of a Victoria's Secret, where addled employees thrust fistfuls of linty sample models at lines of vaguely traumatized ladies. And why not? Bras are just as complicated as plenty of wedding dresses, and women wear them every day.

Next, Katherine brought a front-closure racerback number that was also surprisingly wearable, if a little stiff on the sternum. Soon we settled into a pattern: Every piece that looked suspect to us ended up being a delight. And the ones we had our eye on ended up being the absolute worst. (Low point: a rigid full-cup bra that felt like it had a pair of rocks in the bottom.)

The only downside to the truck is that most of the merch seems to be display only. We were all set to walk away with two Gramercy Balconettes in non-sassy colors, but instead found ourselves ordering online on the store's iPad. The waiting runs counter to the instant gratification you'd normally expect from a truck. No way the Bacon Bacon truck could get away with that. Alas, we get it—stock scarcity is pretty much a given when you're working in just 300 square feet. The only real improvement we can imagine? Sneaking this baby into a Pink or a Macy's.